Look for part-time or hobbyist DJs. These DJs tend to cost less because they have other sources of income and do not have such a large overhead.
Reduce the size of your guest list. The fewer guests you invite the smaller the sound system will be needed.
Keep everything in one room/area. Keep things simple when holding your event. If the DJ only needs to set up once and only needs one sound system then costs will drop. The more places you need sound the more your costs will increase. More equipment = more money.
Pass on extras such as lighting effects, fog machines, etc. Music is what makes or breaks a party and that is what your guests will remember.
Have a friend or family member be your Emcee. The less services a DJ has to offer the more money you can typically save.
Pass on the dance-floor. This is such a waste of money and can cost more than the DJ! Just designate an area for dancing and call it good. People can dance on carpet and any hard surface.
Look for a DJ company that does a high volume business. These companies book a lot of DJs thus offer volume discount pricing in most cases.
Don’t have your event on Saturday. The busiest day of the week for a DJ is Saturday as this is when most everyone’s schedules line up to hold an event. Saturday pricing will always be your most expensive. Friday and Sunday pricing can sometimes be less but they also can be popular days. The most money can be saved Monday –Thursday.